This invention relates to pedometers and, more particularly, to pedometers that determine the distance a user walks, jogs or runs by electronically measuring the length of strides taken by the user.
Pedometers have been used for many years by hikers and long distance walkers to measure the distance traversed. More recently there has been a resurgence in interest in these devices for use in the popular sports of jogging and distance running. In these types of sports, a measure of the athlete's level of achievement requires an accurate determination of distance traversed as well as elapsed time. With the advent of digital stop watches, accurate measurement of elapsed time over a particular course is readily achieved. When the variables of both distance and time are made available to the user, the user's speed may be computed. This information can then be used to pace the user and to evaluate progress in an exercise program or sporting event.
A pedometer for use in the above mentioned sports is one which can accurately measure the distance traversed under a number of varying conditions. For example, the pattern of a jogger may involve activity from slow walking to rapid jogging. A typical jogging path may include hills and winding paths. In the case of a marathon runner, activity may include motion from jogging to sprinting. At high running speeds both of the user's feet may be clear of the ground at the same time. A pedometer suitable for use during these activities must operate accurately over this wide range of conditions.
Many prior art pedometers have been developed which indirectly measure the distance traversed by the user by counting the number of steps taken. The operation of these prior art devices is based on the assumption that the user's stride or distance traversed per step is a constant. The total distance traversed by the user is computed by counting the number of steps taken and multiplying this number by a constant stride distance.
Prior art pedometers employ a variety of techniques for counting the number of steps taken. Most of these techniques rely on the fact that the user's body undergoes an abrupt change in acceleration each time the user's foot contacts the ground. This change in acceleration is detected by any one of a number of acceleration sensitive devices. One of the more common techniques employed in the prior art pedometers is the use of a spring-mounted weight which is coupled to a mechanical counter. At each step, the abrupt change in acceleration causes the weight to exert a force on the spring. This spring force is, in turn, used to advance the counter.
The prior art pedometers possess several limitations which preclude their widespread use in athletic activities such as described above. For example, the assumption that stride length is a constant results in large errors in distance measurement. It has been found that actual stride length may vary considerably as a function of terrain and running speed. Another disadvantage of the prior art pedometers is that the mechanical means for sensing and counting steps has proven unreliable under the varied conditions mentioned above. In many cases the prior art devices with either fail to record a step or, conversely, will record an excessive number of steps.
Further, since many prior art pedometers display only the number of steps taken, the user must mentally convert this data into distance and rate of speed. This presents an unwieldly procedure for a user attempting to determine instantaneous data while running. This condition is further aggravated by the fact that most of the prior art pedometers are designed to be waist-mounted for proper acceleration sensing. When mounted in this position it is difficult, if not, impossible to see the pedometer display while running. The above limitations of the prior art pedometers are even more pronounced when the user is attempting to measure distance traversed during active sports such as tennis, handball and the like.
Accordingly, it is an object of the present invention to provide a new and improved pedometer.
It is another object of the present invention to provide a new and improved pedometer which measures the length of each stride taken by the user.
It is still another object of the present invention to provide a pedometer which measures stride length by electronic means.
It is still another object of the present invention to provide a pedometer which calculates and displays total distance traversed, elapsed time and speed on a wrist-mounted display unit.